Floating type mandrel for tube drawing



I Sept. wADELL 2,358,838

FLOATING TYPE MANDREL FOR TUBE DRAWING Filed March .17, 1945 2 Sheets-Sheet i r? a H D INVENTOR ATTORNEYS Se t. 26, 1944. c; H. WADELL FLOATING TYPE MANDREL FOR TUBE DRAWING 2 Sheets-Sheet 2 Filed March 17, 1943 ll Ill |lvll al'lIlil I Patented Sept. 26, 1944 '1 Carl B. Wadell, Fairilcld, Conn assignor to I Bridgeport Brass Company, Bridgeport, Conn., a corporation of Connecticut Application 11, 1943;, Serial No. 479,425

11 Claims. ((71.205-7) This invention relates to improvements'in tube drawing apparatus, and moreparticularly to a floating plug construction for use in connection with conventional draw-bench constructions and drawing dies.

An object of this invention is to provide a .construction of'this character which will be compensating or self accommodating to imperfections showing relative displacement of the sizing mandrel on its retaining stud. i

Referring to the drawings, a draw bench construction ill including a trough ii and having on the inside surface of the tube being drawn;

and to variations of tube wall thickness thereof.

Another object 01 this invention is to provide a plug construction that will be less subject to breakage or damage as a result of such imperfactions or variations.

A further object of this invention is to provide such construction as will result in great economies in use and in which damage tothe sizing mandrel or sleeve will not necessarily require replacement of said sleeve or of the entire tool.

Still another object of the invention is to provide a construction in which the same mandrel shank may be utilized for differently sized sizing mandrels or sleeves, resulting thereby in eliminating the cost of more than one mandrel shank !or several sizes of sizing mandrels or sleeves.

To the accomplishment of the foregoing and v such other objects as may hereinaftemappear, this invention consists in the novel construction and arrangement of parts hereinafter described and then sought to be defined in the appended claims, reference being had to the accompanying drawings forming a part hereof, which showmerely for the purposes of illustrative disclosure a preferred embodimentof the invention, it being expressly understood, however, that various changes may be made in practice within the scope o! the claims without digressing from the inventive idea.

In the drawings in which similar reference characters denote corresponding parts:

Fig. 1 is a side elevation partially in section of abutment flange 28 and a rounded portion 29'- of reduced diameter which may beprovided with a drive chain I! for moving the draw carriage ll all of usual construction may be employed. A die it is mounted on the draw bench, and tube I5 is adapted to be drawn therethrough by means of the carriage [3 in well known manner.

A floating plug or mandrel i6 is placed within the die and the tube. This plug or mandrel it consists of a mandrel shank I! which is provided with a portion i8 of enlarged, diameter at one end. The shank is provided at this end with an axially extending bore I9 which is countersunk at 20, and provided internally with a tapped or threaded portion 2i, and a portion 22 of re-' duced diameter.

A retaining stud 23 is formed with a threaded portion 24 adapted to threadedly engage the threaded portion 2| of the shank. This stud also has a reduced end portion 25 adapted to fit within the portion 22 of the bore of the shank and a portion 26 adapted to fit within the countersunk portion 20 and to extend outwardly of the shank. A head 21 is provided on the end of the outwardly extending portion 26. This head has an flattened sides '30 to permit application of a tightening tool or the like. The overall outside diameter of the flange 28 is less than the maxia draw bench, die and floating plug construction in accordance with the present invention;

Fig. 2 is a perspective view of the separated parts of the floating plug construction;

Fig. 3 is a longitudinal section of an floating plug construction; v

Fig. 4 is a section taken along line H of Fl 3 viewed in the direction 01' the arrows:

Fig. 5 is a section taken along line 5-5 oiFlg. 3 also viewed in the direction of the arrows; I Fig. 6 is an end view seen in the direction of thearrow6oi'Fig.3;and

Fig. '1 is a iragmentary lonsitudinal section a a assembled mum outside diameter of the shank I l.

The retaining stud 23- carries a loosely fitting sizing mandrel or sleeve 32.- This sleeve mandrel is substantially shorter than the stud, i. e. the

distance between the end Ila of the shank, I] and the flange 2a. The internal diameter otythe sleeve mandrel is greater than the diameteroi.

the portion 28 of the stud 23 so' that said sleeve mandrel may be shifted or moved laterally og'aswell as longitudinally with respect to the stud axis. .The wall 32a of the sleeve may be tapered if desired. The leading edge 33 of-the sleeve is tapered preferably with approximately a 45" taper while its trailing edge 3| is rounded to eliminate any cutting edges on said sleeve mandrel. A suit 7 able coil spring 35 is carried on the stud 23 and serves to urge the sleeve into abutment with the flange 28. The flange 28 has a lesser diameter than the outside diameter of the sleeve 32 and preferably a lesser diameter than that oi the leading-end 32b of said sleeve.

The other end of the shank i1 is provided with tapped bore 31 in which a rod 38 threadedly engages. The opposite end ofthe rod is suitably guided and held in a tail stock 39 in well known manner during the drawing operation.

During the draw, imperfections on the inside surfaces of the tube, and the lack of uniformity of the tube thickness are compensated for by the lateral displaceability of the mandrel sleeve 32 with respect to the stud 23. Thus in Fig. 7,

the said sleeve 32 is shown displaced from contending to produce the position of the sleeve shown in Fig. 7.

Another great advantage of the novel construction is that the same shank and stud can be utilized to mount replaceably several difierent sizes of mandrel sleeves 32.

external diameter of said stud to permit material lateral displacement of said sleeve on said stud, retaining means in conjunction with said stud,

' and means carried on said stud for urging said removably carried on said stud, said mandrel For example, with a stud diameter in the por- I tion 28 of .437 inch mandrel sleeves each having an inside diameter large enough to permit floating action and respectively any outside diameter that allows sufllcient shell wall strength. Other. sizes, too, are contemplated.

Another important advantage is that the mandrel construction described results in great economy. This is so because mandrel sleeves can be replaced on the same mandrel shank without any machining or fitting thereby making it unnecessary to provide separate mandrel shanks for each mandrel sleeve. The savings are in the order of twenty dollars per shank.

Economy also results from the fact that damage to the mandrel sleeve 32 adjacent either of its ends does not require that the sleeve be discarded. It may be trimmed oflf to eliminate the damaged portions. In such event, the spring 35, of course, must'be replaced by a longer spring to compensate for the shortened sleeve length. Since these sleeve mandrels are very expensive, the savings are material and apparent.

In the embodiment'described, the stud 23 is preferably of heat-treated tool steel, the shank can be of any commercial tool steel that may be heat' treated, while the sleeve mandrel is of. cemented tungsten carbide, one commercially available material therefor being "Carboloy."

While specific constructional details have been described, and specific dimensional characteristics mentioned as well as specific materials, it is to be understood that variations in structure, dimensions and materials are contemplated within the scope of the claims. There is no intenmandrel or sleeveinto abutment with said retaining means.

3. A tube drawing mandrel construction comprising a mandrel shank, a stud carried by said shank, a sizing mandrel or sleeve removably carried on said stud, said mandrel or sleeve having a substantially larger internal diameter thanathe external diameter of said stud whereby said mandrel or sleeve may be displaced longitudinally and a material amount laterally on said stud, a retaining head on said stud, and spring means on said stud for urging. said mandrel or sleeve into abutment with said head.

4. A tube drawing mandrel construction comprising a mandrel shank, a stud threadedly engaging said shank, a sizing mandrel or sleeve or sleeve having a substantially larger internal diameter than the external diameter of said stud, and said mandrel or sleeve being shorter than said stud, whereby said mandrel or sleeve may be displaced longitudinally and a substantial amount laterally on said stud, a retaining head on said stud, spring means on said stud for urging said mandrel or sleeve into abutment with said head, and said head having a portion shaped for engagement with a tightening tool.

5. A tube drawing mandrel construction comprising a mandrel shank, a stud threadedly engaging said shank, a sizing mandrel or sleeve removably carried on said stud, said mandrel or sleeve having a substantially larger internal diameter than the external diameter of said stud, and said mandrel or sleeve being shorter than said stud, whereby said mandrel or sleeve may-be displaced longitudinally and a material amount laterally on said stud, a retaining head on said stud, spring means on said stud for urging said mandrel or sleeve into abutment with said head,

7 and said head having a portion shaped for engagement with a tightening tool and means for attachingsaid shank in a tube drawing apparatus.

6. A tube drawing mandrel construction comprising a mandrel shank, a stud threadedly engaging said shank, a sizing mandrel or sleeve'removably carried on said stud, said mandrel or sleeve having a larger internal diameter than the external diameterof said stud, and said mandrel or sleeve being shorter than said stud, whereby said mandrel or sleeve may be displaced iongitudinally and laterally on said-stud, a retaining head on said stud, spring means on said stud for urging said mandrel or sleeve into abutment with said head, and said head having a portion shaped tion of limitation to theexact details described. I

What is claimed is:

1. A tube drawing mandrel construction comprising a mandrelshank, a retaining stud extending from said shankand a sizing mandrel or sleeve carried on said stud and being displaceable longitudinally and a material amount later- 7 ally with respect to the axis thereof.

2. A tube drawing mandrel construction comprising a mandrel shank, a stud carried by said shank, a, sizing mandrel or sleeve removably carried on said stud, said mandrel or sleeve having a for engagement with a tightening tool and said shank having a threaded portion for attachment of said shank in a tube drawing apparatus.

7. A' tube drawing mandrel construction comprising a mandrel shank having a threaded axially extending bore, a'stud threadedly engaging in said bore and extending outwardly thereof, a headed portion on said stud adjacent its outer- -most end, a sizing mandrel or sleeve removably carried on said stud, said mandrel-or sleeve having a larger internal diameter than the external diameter of said stud and said sleeve being shorter in length than said stud, whereby said'ma'ndrel or sleeve may be displaced longitudinally and laterally on said stud, and spring means on said substantially larger internal diameter than the stud for urging said mandrel or sleeve into abutment wih said head, said shank and said stud being of heat treated tool steel and said mandrel .or sleeve being of cemented tungsten carbide.

' sleeve being tapered externally and having a larger internal diameter than the external diameter of said-stud, and said mandrel or sleeve being shorter thansaid stud; whereby said man- 'drel or sleeve may be displaced longitudinally and laterally on said stud, a retaining head on said v stud, spring means on said stud tor urging said mandrel or sleeve into abutment withsaid head,

and said head having a portion shaped for engagement with a tightening tool, and said shank having a threaded portion for attachment of said shank in a tube drawing apparatus.

10. A tube drawing mandrel construction comprising a mandrel shank, a stud threadedly en-= gaging said shank, a sizing mandrel or sleeve removably carried on said stud; said mandrel or sleeve having a rounded edge adjacent its outer periphery at one end and a tapered edge adjacent its outer periphery at its other end, said mandrel having a larger internal diameter than the external diameter of said stud, and said mandrel orsleeve being shorter than said stud, whereby said mandrel or sleeve may be displaced "longitudinally and laterally on said stud, a retaining head on saidstud, spring means on said stud for urging said mandrel or sleeve into abutment with said head, said shank and said stud being of tool steel, and said mandrel or sleeve being of cemented tungsten carbide.

11. A tube drawing mandrel construction comprising a mandrel shank, a stud carried by said shank, a sizing mandrel or sleeve removably carried on said stud and being displaceable longitudinally and a material amount laterally with respect to the axis thereof, and means interposed between the said shank and said mandrel or sleeve and serving as a shock absorber to prevent shock damage to said mandrel or sleeve.

1 CARL H. WADEIL. 

